Hither-to, the RFID technology has been widely used for the purpose of product management. To utilize the RFID technology, IC tags are attached to linen goods such as uniforms or bed sheets used in a hotel. The IC tags attached to such goods need to have flexibility. For this reason, an IC tag made up of a film member provided with an antenna part and an IC chip mounted thereon is used.
In the case where IC tags are attached to linen goods, the IC tags will be washed with the linen goods in the laundry. Therefore, the IC tags attached to such goods need to have strength against external forces and resistance against solutions used in the washing process. As a technique employed to meet this requirement, it is known to cover the body of an IC tag with a covering made of a rubber, resin or the like (see for example, Japanese Patent Application Laid-Open No. 2005-056362 or Japanese Patent Application Laid-Open No. 2007-148735).
However, if the covering that covers the entirety of the IC tag body is not sufficiently thick, the IC chip may break. Moreover, if strong bending and/or twisting force or a pushing load acts on the IC tag in the dewatering step in the washing process, stress will concentrate to a portion of connection of the IC chip and the antenna part, possibly resulting in breakage of the portion of connection. On the other hand, if the covering that covers the entirety of the IC tag is too thick, a problem of insufficient flexibility of the IC tag will arise.
As a solution, it is known to make the thickness of the covering for the portion of the body of the IC tag about the IC chip larger than thickness of the covering for the portion outside the portion about the IC chip (see for example, Japanese Patent Application Laid-Open No. 2007-004323 or Japanese Patent Application Laid-Open No. 2010-122764). Such IC tags can have sufficient overall flexibility, while achieving protection of the portion of connection of the IC chip and the antenna part by relatively thick covering.